Simple Access to 2-Arylbenzo[b]tellurophenes

Arguably, the simplest way for the preparation of benzo[b]tellurophenes has been elaborated. Cyclization of o-haloarylalkynes in the presence of Te-NaOH-DMSO triad occurs by simple mixing of starting materials and heating overnight without the need for dry and inert atmosphere and provides the corresponding benzo[b]tellurophenes in up to 90 % GC-yield. Catalytic telluration of aryl iodide substrates extends the applicability of the developed cyclization cascade to substrates that are not suitable for the direct SNAr/5-endo-dig cyclization approach. Successful SEAr in the third position of benzo[b]tellurophene provides a synthetic intermediate for the preparation of Te analogues of selective estrogen receptor modulator (SERM) raloxifene.